Non-contact detection of electrical energy

ABSTRACT

Methods, systems, and apparatus, including computer programs stored on a computer-readable storage medium, for obtaining a reference phase signal that is synchronized with an alternating current (AC) phase of a multi-phase electrical power distribution system. The apparatus obtains output signals from sensors, each output signal representative of an electromagnetic emission detected by a respective sensor. The apparatus identifies, based on comparing respective phases of the output signals to the reference phase signal, a particular AC phase of the multi-phase electrical power distribution system associated with a source of the emissions. The apparatus provides an indication of the particular AC phase to a user.

CROSS REFERENCE TO RELATED APPLICATION

This patent application is a continuation (and claims the benefit ofpriority under 35 USC 120) of U.S. patent application Ser. No.16/429,506, filed Jun. 3, 2019. The disclosure of the prior applicationis considered part of (and is incorporated by reference in) thedisclosure of this application.

BACKGROUND

Electric generating power plants commonly produce three phasealternating current (AC) electrical power. The voltage of thetransmitted and distributed electric power can be increased or reducedby transformers located at substations or switching yards of on feederslocated between power plants and loads. The three-phase power can bedistributed through an electrical grid to provide power to loads such asresidential, commercial, and industrial properties. Residential homesand small businesses (e.g., retail stores) are typically fed from onephase of an electrical distribution system. In some instances, theincreasing use of alternative energy sources by residential and smallbusinesses to reduce their electrical draw from the electrical grid (andin some instances, create reverse electrical power flow to the grid) cancause, or increase, phase imbalances in regions of the electrical grid.There are other causes of phase imbalance as well, for instance theassignment of unbalanced loads to the phases within industrialfacilities or along three phase feeders. Often these imbalances occurover time as loads are moved or new loads assigned. Load imbalance canhave negative effects, particularly on the efficiency of three-phasetransformers, and often the phase assignments of loads are not welldocumented.

SUMMARY

This specification relates to detecting the phases of loads inelectrical distribution systems. More specifically, the disclosurerelates to a non-contact phase identifier and operations of a phaseidentifier. A phase identifier is configured to identify the individualphase of a load in a three-phase alternating current electrical powerdistribution system (e.g., a three-phase AC system).

An example implementation of the phase identifier is to identify thephase of a residential home connected to an electrical grid. Residentialproperties and small businesses are typically connected to one phase ofa three-phase electrical grid. Recently there has been an increase inthe number of homes with photovoltaic solar panel systems that canprovide electrical power back to the grid. Grid-connected solar panelsreduce the electric load of a home, so that the home can function asboth a load, and at certain times, as a source to the grid. If thesehomes are not connected in a balanced manner, the homes can cause phaseimbalances in the grid, which decreases grid efficiency.

A three-phase electrical distribution system is most efficient when theloads on each phase are equally balanced. To aid in balancing loads onan electrical distribution system, the phase of existing loads can beidentified. A phase identifier can identify the phase of loads orsources without making physical contact with power lines.

The phase identifier operates by detecting emissions from a nearby loadsuch as a house connected to an electrical grid. Emissions can include,but are not limited to, electric fields, magnetic fields, infraredenergy, ultraviolet energy, and visible light. The emissions correspondto the electrical power signals supplied to electrical loads in thehome, and therefore can be used to determine which phase of an electricpower distribution system is being supplied to the loads in the house.In some implementations, the phase identifier can detect and aggregatemultiple types of emissions to determine which phase of the multi-phasesystem is supplied to the local loads (e.g., within a house).

In general, innovative aspects of the subject matter described in thisspecification can be embodied in an electrical phase identificationdevice that includes sensors including a first sensor configured todetect a first type of emission and a second sensor configured to detecta second type of emission, a power source, and a control system. Thecontrol system is coupled to the sensors and the power source. Thecontrol system includes one or more processors and a data store coupledto the one or more processors. The data store has instructions storedthereon which, when executed by the one or more processors, causes theone or more processors to perform operations that include: obtaining areference phase signal that is synchronized with an alternating current(AC) phase of a multi-phase electrical power distribution system;obtaining output signals from the sensors, each output signalrepresentative of an electromagnetic emission detected by a respectivesensor; identifying, based on comparing respective phases of the outputsignals to the reference phase signal, a particular AC phase of themulti-phase electrical power distribution system associated with asource of the emissions; and providing an indication of the particularAC phase to a user.

This and other implementations can each optionally include one or moreof the following features.

In some implementations, obtaining the reference phase signal includesreceiving a GPS clock signal that is synchronized with the AC phase ofthe multi-phase electrical power distribution system.

In some implementations, the operations include transmitting theindication of the particular AC phase to a server system.

In some implementations, identifying the particular AC phase of themulti-phase electrical power distribution system includes determiningthat the respective phases of the output signals from the first sensorand the second sensor are within an expected lagging range from thereference phase signal that is associated with the particular AC phaseof the multi-phase electrical power distribution system.

In some implementations, identifying the particular AC phase of themulti-phase electrical power distribution system includes combining theoutput signals into a base output signal and comparing a phase of thebase output signal to the reference phase signal.

In some implementations, identifying the particular AC phase of themulti-phase electrical power distribution system includes identifyingone of the output signals as a dominant signal and comparing a phase ofthe dominant signal to the reference phase signal.

In some implementations, the power source includes a battery or a solarcell.

In some implementations, the operations include identifying one of theoutput signals as an outlier signal, based on a phase of the one of theoutput signals falling outside of an expected lagging range from thereference phase signal, and identifying the particular AC phase includesidentifying the particular AC phase based on comparing respective phasesof the output signals, other than the outlier signal, to the referencephase signal.

In some implementations, the first sensor is an electric field sensor,and the second sensor is one of a magnetic field sensor, an infraredsensor, a visible light sensor, or an ultraviolet light sensor.

In some implementations, the sensors, power source, and control systemare enclosed in a portable housing.

In another general aspect, innovative aspects of the subject matterdescribed in this specification can be embodied in methods that includeactions of obtaining a reference phase signal that is synchronized withan AC phase of a multi-phase electrical power distribution system,obtaining output signals from two or more sensors, each output signalrepresentative of an electromagnetic emission detected by a respectivesensor, identifying, based on comparing respective phases of the outputsignals to the reference phase signal, a particular AC phase of themulti-phase electrical power distribution system associated with asource of the emissions, and providing an indication of the particularAC phase to a user. Other implementations of this aspect includecorresponding systems, apparatus, and computer programs, configured toperform the actions of the methods, encoded on computer storage devices.

Among other advantages, implementations may improve the overallefficiency of electrical power systems, e.g., power transmission anddistributions systems. For example, a phase identifier can identify aparticular phase of multi-phase electrical power distribution system toaid in balancing loads. An electrical distribution system is mostefficient when the loads on each phase are equally balanced.Implementations provide for non-intrusive phase identification inelectrical power systems. A phase identifier does not require physicalelectrical connections to the electrical power systems. A phaseidentifier can identify the phase of loads or sources without makingphysical contact with power lines.

The details of one or more embodiments of the subject matter describedin this specification are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages of thesubject matter will become apparent from the description, the drawings,and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an exemplary environment in which an electricalphase identifier can be used.

FIG. 2 is a block diagram of an example electrical phase identifier.

FIG. 3A-3D are diagrams illustrating example phase differences ofvarious emissions.

FIG. 4 is a flow diagram that illustrates example processes foridentifying the phase of emissions.

FIG. 5 depicts a schematic diagram of a computer system that may beapplied to any of the computer-implemented methods and other techniquesdescribed herein.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

A phase identifier is configured to identify the individual phase of aload in a three-phase alternating current electrical power distributionsystem (e.g., a three-phase AC system). For example, the phaseidentifier operates by detecting emissions from a nearby load such as ahome connected to an electrical grid. Emissions can include, but are notlimited to, electric fields, magnetic fields, infrared energy,ultraviolet energy, and visible light. The emissions are linked to theelectrical power signals supplied to electrical loads in the home, andtherefore can be used to determine which phase of a power system isbeing supplied to the loads in the home. In some implementations, thephase identifier detects and aggregates multiple types of emissions todetermine which phase of the multi-phase system is supplied to one ormore loads (e.g., houses).

An example implementation of the phase identifier is to identify thephase of a residential home, such as a house, connected to an electricalgrid. Residential properties are typically connected to one phase of agrid. Recently there has been an increase in the number of homes withphoto-voltaic solar panel systems that can provide electrical power tothe load, and back to the grid. Grid-connected solar panels reduce theelectric load of a home, so that the home can function as both a loadand source to the grid. This can cause phase imbalances in the grid,which decreases grid efficiency.

The application of phase shifting transformers, such as delta-startransformers, and the application of single phase transformers toline-line outputs of the secondary side, can create positive or negative60 degree phase shifts between the primary and the secondary sides ofdistribution interconnection, for both voltages and currents. Referencesto phases A, B, and C in this specification refer to the secondary side.The appropriate phase shifts can be added when referring back to thedistribution primary side.

Implementations of the present disclosure will be discussed in furtherdetail with reference to an example context, however, it should beappreciated that the implementations discussed may be applicable moregenerally to any load connected to a phase of an electrical grid. Theexample context includes a house in a residential neighborhood. It isalso appreciated, however, that implementations of the presentdisclosure can be realized in other appropriate contexts, for example,detecting electrical phases used to power residential, retail, orcommercial property. In some cases, the phase identifier can be used toidentify which phase of a three-phase system a particular piece ofelectrical equipment is operating on, e.g., in an industrial complexsuch as a large factory.

FIG. 1 is a diagram of an exemplary environment 100 in which anelectrical phase identifier 105 may be used. For example, a phaseidentifier 105 detects emissions 110 from a house 115 connected to anelectrical distribution system (e.g., a load of an electrical grid). Thephase identifier 105 receives a reference signal 118. For example, thereference signal 118 is a reference timing signal which can be sent(e.g., broadcasted) from a server 120 at a grid substation 140. In someimplementations, the reference signal 118 can come from a componentwithin the phase identifier 105, such as a previously synchronizedreference clock, or from any power source of known phase. The phaseidentifier 105 compares the detected emissions 110 with the referencesignal to identify the phase 130 of the house 115. The phase identifier105 provides indications of the specific phase 130 of the house 115 to auser 125.

In more detail, the electrical distribution system in FIG. 1 distributesthree phase AC power to houses 108, 109, and 115 within a residentialarea. Each house acts as a load on the electrical distribution system,and each is fed from one phase of the electrical grid. For instance,houses 108 and 109 are connected to phases B and C, respectively. House115 is connected to phase A.

A user 125 directs a phase identifier 105 towards the house 115. Thephase identifier 105 can be portable, i.e., sized and shaped to enablethe user 125 to carry the phase identifier 105 by hand. The sensors,power source, and control system of the phase identifier 105 can beenclosed in a portable housing. The phase identifier 105 can include anaccessory structure, e.g., a handle, that permits the user 125 totransport the device by hand. In some examples, the phase identifier 105can be mounted to a piece of equipment, e.g., a helmet or vest of theuser 125. In some examples, the phase identifier 105 can be mounted to avehicle.

The phase identifier 105 can be mounted to any type of vehicle, such asa manually operated, remotely-piloted, or autonomous vehicle. Thevehicle can be ground-based or airborne. For example, a phase identifier105 can be mounted on an autonomous ground-based vehicle. The phaseidentifier can use sensors such as a camera to identify loads, and canorient its detectors toward the loads.

The phase identifier 105 includes one or more detectors. The detectorsof the phase identifier 105 are configured to detect emissions fromelectrical loads when within a detectable range and field of view. Forexample, the detectors can be electric field detectors, magnetic fielddetectors, infrared energy detectors, ultraviolet energy detectors, andvisible light detectors.

The detectors of the phase identifier 105 collect emissions 110 from ahouse 115. For example, when a user 125 aims the detectors of the phaseidentifier 105 toward the house 115, the detectors receive emission 110signals from the house 115. Emission signals received by the detectorscan include, but are not limited to, electric field emissions, magneticfield emissions, infrared energy emissions, ultraviolet energy emission,and visible light emissions. The phase identifier 105 can includeshielding to eliminate noise signals. For example, the shielding canblock the emissions signals from houses 108 and 109.

Since the house 115 is connected to one phase of the AC grid, the phaseof emissions 110 from the house 115 correlate to the specific phase 130that feeds the house 115. Generally, emissions 110 from the house areexpected to either align with or lag the specific electrical phase 130that drives loads that create the emissions (e.g., lights, motors,compressors, etc. that are in the house). The phase identifier 105determines which specific phase 130 the house 115 is connected to, basedon the detected emissions 110. To make this determination, the phaseidentifier 105 compares the phase of emissions 110 detected from thehouse 115 to a reference signal 118.

The reference signal 118 is synchronized to a particular AC phase of theAC grid. For example, the timing of the reference phase signal can becorrelated with the AC variations of one of three AC power phases at apower substation so that the reference phase signal provides an accuraterepresentation of AC power phase. The reference signal 118 can begenerated on a server 120 at a grid substation 140 or other location onthe grid where the phase relationships are known.

The reference signal 118 is sent to the phase identifier 105. Forexample, the grid substation 140 can transmit the reference signal to asatellite 135. The phase identifier 105 then receives the referencesignal from the satellite 135. For example, the server 120 at the gridsubstation 140 and the phase identifier 105 can include highly accuratereference clocks, such as GPS clocks. In some examples, a GPS clocksignal can be synchronized to one of the phases of the AC grid and usedas the reference signal. The phase identifier 105 compares the referencesignal 118 to the emission 110 from the house 115 to determine whichspecific phase 130 the house 115 is connected to.

In the example in FIG. 1, the house 115 is connected to phase A of theelectrical grid. The phase identifier 105 collects emissions 110 fromthe house 115. The emissions 110 can include, for example, visible lightemissions. Visible light emissions generally align with the electricalphase of the power source. For example, if the power source is phase Aof an electrical grid, the phase of the visible light emissions isexpected to approximately align with phase A of the electrical grid.

The reference signal 118 can be synchronized with any of the threephases of AC power. If the reference signal 118 is synchronized withphase A, and the house 115 is connected to phase A, the reference signal118 and the phase of visible light emissions are expected toapproximately align. If the reference signal is synchronized with phaseB, the reference signal 118 and the phase of visible light emissionswill be offset by approximately 120 degrees. If the reference signal 118is synchronized with phase C, the reference signal 118 and the phase ofvisible light emissions will be offset by approximately 240 degrees.

Other sources of emissions, such as magnetic field emissions, may notalign with the phase of the power source, but may lag in phase by ninetydegrees or less. For example, if the reference signal 118 issynchronized with phase A, and the house 115 is connected to phase A,the phase of magnetic field emissions from house 115 will lag thereference signal 118 by a phase angle less than 120 degrees. That is,although the magnetic field emissions will lag the reference phase, theygenerally will not lag by so much as to fall behind the phase B signals(e.g., assuming phase B lags phase A by 120 degrees). If the referencesignal 118 is synchronized with phase B, the phase of magnetic fieldemissions from house 115 (connected to phase A) will lag the referencesignal 118 by a phase angle between approximately 240 and 360 degrees.If the reference signal 118 is synchronized with phase C, the phase ofmagnetic field emissions from house 115 will lag the reference signal118 by a phase angle between approximately 120 and 240 degrees.

Based on comparing the known phase of the reference signal 118 to theunknown phase of the detected emission 110, the phase identifier 105 candetermine the specific phase 130 of the AC power grid that the house 115is connected to. For example, if the reference signal 118 issynchronized with phase A, and the visible light emissions from thehouse 115 approximately align with the reference signal 118, the phaseidentifier 105 can determine that the house 115 is connected to phase Aof the electrical grid. As another example, if the reference signal 118is synchronized with phase A, and the magnetic field emissions from thehouse 115 are offset from the reference signal 118 by a phase anglebetween approximately 0 and 120 degrees, the phase identifier 105 candetermine that the house is connected to phase A.

The phase identifier 105 can detect more than one type of emissions 110.For example, the phase identifier can detect both light emissions andmagnetic field emissions. For example, if the light emissionsapproximately align with the reference signal, which is synchronizedwith phase A, and the magnetic field emissions are offset from thereference signal by a phase angle between approximately 0 and 120degrees, the phase identifier 105 can aggregate the data to determinethat the house is connected to phase A.

The phase identifier 105 provides indications of the specific phase 130of the house 115 to the user 125. The indication may be, for example, adigital display screen that can display the letters “A,” “B,” or “C,”according to the identified phase.

The phase identifier 105 can also communicate the identified phase ofthe house 115 back to the server 120 at the grid substation 140. Theidentified phases of various loads can be saved and referenced forvarious purposes, such as mapping the electrical distribution system,tracking phase imbalance, and/or correcting phase imbalance.

FIG. 2 is a block diagram of an example electrical phase identifier 200.The phase identifier 200 can include one or more detectors 210, acontrol system 212, and a power source 230. The control system 212 caninclude a processor 215, a GPS 220, an inertial measurement unit (IMU)225 (e.g., an accelerometer), an output module 235, a display 240, and aclock 245. The example phase identifier 200 can also include acommunications interface 250.

The electrical phase identifier 200 detects emissions from a load on anelectrical distribution system. The phase identifier 200 has one or moredetectors 210 that collect various emissions. The detectors can be, forexample, electric field detectors, magnetic field detectors, infraredenergy detectors, ultraviolet energy detectors, and visible lightdetectors. Upon detection of one or more emissions, the detectors 210convert the electromagnetic energy from the emissions 202 intoelectrical signals.

The detectors 210 send the collected emissions data to the processor215. The processor receives the signal data for all emissions 202. Theprocessor 215 correlates the signal data to determine a base signal. Todetermine the base signal, the processor 215 can focus on a dominant oneof the detector output signals. For example, if one detector outputsignal is particularly strong in comparison with other detector outputsignals such as light flicker signal or magnetic field signal, theprocessor 215 can select that signal as the base signal.

In other examples, there is a range of characteristics of emissions. Therange of characteristics can be a range of phases such that the phasesare bounded and so indicate the particular electrical phase they arederived from. When there is a range of characteristics, the signals canbe aggregated or superimposed to determine the base signal. Theprocessor 215 can sum the particular sensed excitations for a wide rangeof electromagnetic fields, including those that obey superposition,because the fields can be shown to be bounded in phase variation.

The processor 215 receives a reference signal synchronized with an ACphase of a multi-phase electrical power distribution system. Thereference signal can come from a remote location, such as an electricalgrid substation, and can be communicated to the phase identifier 200through a communications interface 250. In another example, the clock245 within the phase identifier 105 is previously synchronized with aparticular phase of the AC grid. In this example, the phase identifieris self-contained, and does not communicate externally to obtain thereference signal.

The processor 215 compares the base signal derived from the detectedemissions 202 to the reference signal. The processor 215 measures thephase difference between the detected emissions 202 and the referencesignal. Based on the measured phase difference, the processor 215identifies the phase of the emissions 202.

FIG. 3A-3D are diagrams showing example phase differences of variousemissions, compared to reference signals. In each example in FIG. 3A-3D,the reference signal is synchronized with the “A” phase of an electricaldistribution. The source of detected emissions is a load, such as ahouse, connected to the “A” phase of the electrical distribution system.

FIG. 3A shows a sine wave representing the reference signal 310A and adetected emissions signal 320A. The horizontal axis represents time,while the vertical axis represents amplitude. The phase difference 330Ais the time delay between the signals. A lagging signal is shifted tothe right, while a leading signal is shifted to the left.

The reference signal 310A corresponds to the “A” phase of the electricalgrid. The detected emissions signal 320A can represent anyelectromagnetic field signal emitted from the house 115. For example,the detected emissions signal 320A can represent a magnetic field,ultraviolet radiation, infrared radiation, or visible light radiation.

The processor 215 of the phase identifier measures the phase differencebetween the reference signal and the emitted signal. Based on themeasured phase difference, the phase identifier identifies theelectrical phase of the house 115.

In the example of FIG. 3A, the detected emission signal 320A lags thereference signal 310A by less than 90 degrees. Thus, the phaseidentifier can determine that the detected emissions signal 320A islikely produced by an electrical load of a house that is connected tothe reference phase, which is phase “A.”

If the detected emissions signal 320A lags the reference signal 310A bymore than 120 degrees but less than 240 degrees, the source of theemissions is likely connected to phase “B” of the electricaldistribution system. If the detected emissions signal 320A lags thereference signal 310A by more than 240 degrees, the source of theemissions is likely connected to phase “C” of the electricaldistribution system.

FIGS. 3B, 3C, and 3D are rotating phasor diagrams of AC electricalsignals. The three phases of the AC electrical distribution system arerepresented by vectors A, B, and C, each offset by 120 degrees. Thevertical vectors 310B, 310C, and 310D represent the reference signals.Additional vectors on the phasor diagrams represent detected emissionssignals. The length of each vector represents the strength, oramplitude, of the signal.

In the example in FIG. 3B, the emissions signal 320B is detected by anelectric field detector within a phase identifier, while aimed at ahouse. The emissions signal 320B from the electric field aligns with thereference signal 310B. The reference signal 310B corresponds to the “A”phase of the electrical distribution system. Therefore, the phaseidentifier determines that the house is connected to the “A” phase ofthe electrical distribution system.

The detected emissions may not align exactly with the reference signalor with a particular phase of an electrical distribution system. Foreach phase, there may be an expected lagging range for detectedemissions. For example, a certain detected emission from a house mayhave an expected lagging range of 10 to 50 degrees from the electricalphase. The expected lagging range may be dependent on the type ofemission.

Since the reference signal corresponds with only one phase of theelectrical distribution system, the expected lagging ranges will beoffset by 120 degrees for each phase. For example, emissions from ahouse connected to phase “A” may have an expected lagging range of 10 to50 degrees compared to phase “A.” Since the reference signal in thisexample corresponds with phase “A,” the expected lagging range of theemissions signals compared to the reference signal is also 10 to 50degrees.

As another example, emissions from a house connected to phase “B” mayhave an expected lagging range of 10 to 50 degrees compared to phase“B.” Since the reference signal in this example corresponds with phase“A,” the expected lagging range of the emissions signals compared to thereference signal is 130 to 180 degrees. That is, a house connected tophase “B” is expected to emit signals that lag emissions from a houseconnected to phase “A” by approximately 120 degrees.

In the example in FIG. 3C, three emissions signals 320C, 322C, and 324Care detected by a phase identifier while aimed at a house. The threeemissions signals can be detected by, for example, an infrared detector,a magnetic field detector, and a visible light detector within the phaseidentifier. Of the three detected emissions signals, none align exactlywith the reference signal 310C. However, all detected emissions fallwithin an expected lagging range 330C of the reference signal 310C. Theexpected lagging range 330C corresponds with loads connected to phase“A.” The phase identifier can compare the emissions signals to thereference signal 310C to determine that the phase of the house is “A.”

In the example in FIG. 3D, three emissions signals 320D, 322D, and 324Dare detected by a phase identifier while aimed at a house. The threeemissions signals can be detected by, for example, an infrared detector,a magnetic field detector, and a visible light detector within the phaseidentifier. Of the three detected emissions signals, none align exactlywith the reference signal 310D. Two of the detected emissions signals320D and 322D fall within an expected lagging range 330D of thereference signal 310D. The expected lagging range 330D corresponds withloads connected to phase “A.”

The detected emissions signal 324D falls within an alternate expectedlagging range 340D of the reference signal 310D. The expected laggingrange 340D corresponds with loads connected to phase “B.” To determinethe phase of the house in FIG. 3D, the phase identifier can process thethree emissions signals 320D, 322D, and 324D in various ways.

In some implementations, the phase identifier can measure the phasedifference of each individual emissions signal 320D, 322D, and 324D ascompared to the reference signal 310C. If the majority of the emissionssignals 320D align with the expected lagging range of a particularphase, the phase identifier can conclude that the house is connected tothat phase. For example, since signals 320D and 322D are within theexpected lagging range for phase “A,” while signal 324 is instead in theexpected lagging range for phase “B,” the phase identifier can determinethat, based on the majority of the emissions signals, the house isconnected to phase “A.”

In some implementations, the phase identifier can focus on a dominantsignal. If one signal is stronger, and therefore larger in amplitude,than other signals, the phase identifier can identify the phase based oncomparing only the dominant signal to the reference signal. In theexample of FIG. 3D, signal 324D has the largest amplitude. If the phaseidentifier is programmed to identify the phase based on the dominantsignal, the phase identifier can determine that, based on the phase ofthe strongest signal 324D, the house is connected to phase “B.”

In some implementations, the phase identifier can aggregate orsuperimpose multiple emissions signals. The phase identifier candetermine the phase of the load based on the summation of all of thedetected signals.

In some implementations, the phase identifier can recognize and ignoreoutliers. For example, in the example in FIG. 3D, it is possible thatsignals 320D and 322D represent emissions from the target house, whilesignal 324D represents an emission from another nearby source. Forexample, the signal 324D may come from a neighboring house, or from anelectrical device that is not connected to the electrical distributionsystem. The phase identifier can be configured to recognize anddisregard outliers so as to reduce the effects of noise andinterference.

Referring back to FIG. 2, once the processor 215 identifies the phase ofa load, such as the house 115, the processor 215 provides the identifiedphase to the output module 235. The output module can provide anindication of which power phase of the electrical grid the house 115 isconnected through the display 240. The display 240 can be, for example,a digital display screen that can display the letters “A,” “B,” or “C,”according to the identified phase. In another example, the indicationcan be a set of three LEDs labeled “A,” “B,” and “C.” The LED next tothe appropriate letter can illuminate when the phase of the load isidentified. Alternatively, the display 240 can be a dial with anindicator that points to either “A,” “B,” or “C.” The display 240provides an individual user near the source of emissions 202 with anindication of the phase of the source.

The display 240 can include an indication that a signal is not strongenough, or that there is too much noise for the phase identifier to makea phase determination. This indication can be, for example, a writtenmessage on a digital display screen, such as “Weak Signal Strength” or“High Noise Level.” Alternatively, the indication can be an LED with alabel such as “error.” These indications can signal to the user forexample, that the phase identifier should be moved closer to the sourceof emissions, or that nearby emissions sources should be shielded.

The output module 235 can communicate externally via the communicationinterface. The communication interface can be used, for example, to sendthe identified phase of a load to a remote server or a mobile computingdevice, e.g., a smartphone, tablet computer, or laptop computer.

The phase identifier 200 includes a GPS 220 and an IMU 225. The GPS 220determines the geographical location of the phase identifier. The IMU225 can be used for gimbal details to correct for specific targetlocation. The GPS 220 and IMU 225 together can determine the location,orientation, and/or speed of the phase identifier 200. In someimplementations, the GPS 220 and IMU 225 can communicate the location,orientation, and/or speed information to a vehicle on which the phaseidentifier 200 is mounted. The vehicle can use the information from theGPS 220 and IMU 225 to navigate near loads and orient the detectors 210of the phase identifier 200.

The phase identifier 200 also includes a power source 230. The powersource 230 can be internal, such a battery or solar cell. In someimplementations, the phase identifier 200 can use external power througha power cord that is plugged into a power outlet. For example, the phaseidentifier 200 can obtain external power through a power cord connectedto a vehicle.

FIG. 4 depicts a flowchart of an example process 400 for identifying thephase of emissions. In some implementations, the process 400 can beprovided as one or more computer-executable programs executed using oneor more processors or microcontrollers. In some examples, the process400 is executed by a phase identification device such as phaseidentifier 200 of FIG. 2.

The phase identifier receives emission signals from one or more sensors(402). The sensors can be, for example, electric field sensors, magneticfield sensors, ultraviolet sensors, infrared sensors, and/or visiblelight sensors. The phase identifier can process the emissions signalsby, for example, aggregating multiple emissions signals and/oridentifying a dominant signal.

The phase identifier secondly receives a reference phase signal that issynchronized with an alternating current (AC) phase of a multi-phaseelectrical power distribution system (404). The reference signal cancome from a component within the phase identifier, such as a previouslysynchronized reference clock, from a remote location, such as a serverlocated at a grid substation, and/or from any power source of knownphase.

The phase identifier identifies, based on comparing respective phases ofthe output signals to the reference phase, a particular AC phase of themulti-phase electrical power distribution system associated with asource of the emissions (406). The phase identifier can determine thatthe source of the emissions is fed from phase “A,” “B,” or “C” of theelectrical distribution system.

The phase identifier provides an indication of the particular AC phaseto a user (408). The indication can be provided, for example, on adigital display screen or via LED light indications. The identifiedphase can also be communicated to a remote server to be saved andreferenced for various purposes, such as mapping the electricaldistribution system and tracking phase imbalance.

FIG. 5 is a schematic diagram of a computer system 500. The system 500can be used to carry out the operations described in association withany of the computer-implemented methods described previously, accordingto some implementations. In some implementations, computing systems anddevices and the functional operations described in this specificationcan be implemented in digital electronic circuitry, in tangibly-embodiedcomputer software or firmware, in computer hardware, including thestructures disclosed in this specification (e.g., system 500) and theirstructural equivalents, or in combinations of one or more of them. Thesystem 500 is intended to include various forms of digital computers,such as laptops, desktops, workstations, personal digital assistants,servers, blade servers, mainframes, and other appropriate computers,including vehicles installed on base units or pod units of modularvehicles. The system 500 can also include mobile devices, such aspersonal digital assistants, cellular telephones, smartphones, and othersimilar computing devices. Additionally, the system can include portablestorage media, such as, Universal Serial Bus (USB) flash drives. Forexample, the USB flash drives may store operating systems and otherapplications. The USB flash drives can include input/output components,such as a wireless transducer or USB connector that may be inserted intoa USB port of another computing device.

The system 500 includes a processor 510, a memory 520, a storage device530, and an input/output device 540. Each of the components 510, 520,530, and 540 are interconnected using a system bus 550. The processor510 is capable of processing instructions for execution within thesystem 500. The processor may be designed using any of a number ofarchitectures. For example, the processor 510 may be a CISC (ComplexInstruction Set Computers) processor, a RISC (Reduced Instruction SetComputer) processor, or a MISC (Minimal Instruction Set Computer)processor.

In one implementation, the processor 510 is a single-threaded processor.In another implementation, the processor 510 is a multi-threadedprocessor. The processor 510 is capable of processing instructionsstored in the memory 520 or on the storage device 530 to displaygraphical information for a user interface on the input/output device540.

The memory 520 stores information within the system 500. In oneimplementation, the memory 520 is a computer-readable medium. In oneimplementation, the memory 520 is a volatile memory unit. In anotherimplementation, the memory 520 is a non-volatile memory unit.

The storage device 530 is capable of providing mass storage for thesystem 500. In one implementation, the storage device 530 is acomputer-readable medium. In various different implementations, thestorage device 530 may be a floppy disk device, a hard disk device, anoptical disk device, a tape device, or a solid state device.

The input/output device 540 provides input/output operations for thesystem 500. In one implementation, the input/output device 540 includesa keyboard and/or pointing device. In another implementation, theinput/output device 540 includes a display unit for displaying graphicaluser interfaces.

The features described can be implemented in digital electroniccircuitry, or in computer hardware, firmware, software, or incombinations of them. The apparatus can be implemented in a computerprogram product tangibly embodied in an information carrier, e.g., in amachine-readable storage device for execution by a programmableprocessor; and method steps can be performed by a programmable processorexecuting a program of instructions to perform functions of thedescribed implementations by operating on input data and generatingoutput. The described features can be implemented advantageously in oneor more computer programs that are executable on a programmable systemincluding at least one programmable processor coupled to receive dataand instructions from, and to transmit data and instructions to, a datastorage system, at least one input device, and at least one outputdevice. A computer program is a set of instructions that can be used,directly or indirectly, in a computer to perform a certain activity orbring about a certain result. A computer program can be written in anyform of programming language, including compiled or interpretedlanguages, and it can be deployed in any form, including as astand-alone program or as a module, component, subroutine, or other unitsuitable for use in a computing environment.

Suitable processors for the execution of a program of instructionsinclude, by way of example, both general and special purposemicroprocessors, and the sole processor or one of multiple processors ofany kind of computer. Generally, a processor will receive instructionsand data from a read-only memory or a random access memory or both. Theessential elements of a computer are a processor for executinginstructions and one or more memories for storing instructions and data.Generally, a computer will also include, or be operatively coupled tocommunicate with, one or more mass storage devices for storing datafiles; such devices include magnetic disks, such as internal hard disksand removable disks; magneto-optical disks; and optical disks. Storagedevices suitable for tangibly embodying computer program instructionsand data include all forms of non-volatile memory, including by way ofexample semiconductor memory devices, such as EPROM, EEPROM, and flashmemory devices; magnetic disks such as internal hard disks and removabledisks; magneto-optical disks; and CD-ROM and DVD-ROM disks. Theprocessor and the memory can be supplemented by, or incorporated in,ASICs (application-specific integrated circuits).

To provide for interaction with a user, the features can be implementedon a computer having a display device such as a CRT (cathode ray tube)or LCD (liquid crystal display) monitor for displaying information tothe user and a keyboard and a pointing device such as a mouse or atrackball by which the user can provide input to the computer.Additionally, such activities can be implemented via touchscreenflat-panel displays and other appropriate mechanisms.

The features can be implemented in a computer system that includes aback-end component, such as a data server, or that includes a middlewarecomponent, such as an application server or an Internet server, or thatincludes a front-end component, such as a client computer having agraphical user interface or an Internet browser, or any combination ofthem. The components of the system can be connected by any form ormedium of digital data communication such as a communication network.Examples of communication networks include a local area network (“LAN”),a wide area network (“WAN”), peer-to-peer networks (having ad-hoc orstatic members), grid computing infrastructures, and the Internet.

The computer system can include clients and servers. A client and serverare generally remote from each other and typically interact through anetwork, such as the described one. The relationship of client andserver arises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinventions or of what may be claimed, but rather as descriptions offeatures specific to particular implementations of particularinventions. Certain features that are described in this specification inthe context of separate implementations can also be implemented incombination in a single implementation. Conversely, various featuresthat are described in the context of a single implementation can also beimplemented in multiple implementations separately or in any suitablesubcombination. Moreover, although features may be described above asacting in certain combinations and even initially claimed as such, oneor more features from a claimed combination can in some cases be excisedfrom the combination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the implementations described above should not beunderstood as requiring such separation in all implementations, and itshould be understood that the described program components and systemscan generally be integrated together in a single software product orpackaged into multiple software products.

Thus, particular implementations of the subject matter have beendescribed. Other implementations are within the scope of the followingclaims. In some cases, the actions recited in the claims can beperformed in a different order and still achieve desirable results. Inaddition, the processes depicted in the accompanying figures do notnecessarily require the particular order shown, or sequential order, toachieve desirable results. In certain implementations, multitasking andparallel processing may be advantageous.

The invention claimed is:
 1. An electrical phase identification devicecomprising: a sensor configured to detect an electromagnetic emission;and a control system coupled to the sensor, the control systemcomprising one or more processors and a data store coupled to the one ormore processors having instructions stored thereon which, when executedby the one or more processors, causes the one or more processors toperform operations comprising: obtaining a reference signal; obtainingan output signal from the sensor, the output signal representative ofthe electromagnetic emission detected by the sensor; identifying, basedon comparing the output signal to the reference signal, an electricalphase associated with a source of the electromagnetic emission; andoutputting an indication of the electrical phase.
 2. The device of claim1, wherein comparing the output signal to the reference signal comprisesdetermining a first phase offset between the output signal and thereference signal.
 3. The device of claim 2, wherein identifying theelectrical phase associated with the source of the electromagneticemission comprises: determining a second phase offset between thereference signal and an alternating current (AC) phase of a multi-phaseelectrical power distribution system; and determining the electricalphase associated with the source of the electromagnetic emission basedon (i) the first phase offset between the output signal and thereference signal and (ii) the second phase offset between the referencesignal and the AC phase of the multi-phase electrical power distributionsystem.
 4. The device of claim 1, wherein the reference signal comprisesa global positioning system clock signal.
 5. The device of claim 1,wherein the sensor is configured to detect the electromagnetic emissionfrom a position that is remote from the source of the electromagneticemission.
 6. The device of claim 1, wherein the sensor and the controlsystem are enclosed in a portable housing.
 7. The device of claim 1,wherein identifying the electrical phase associated with the source ofthe electromagnetic emission comprises identifying a particular AC phaseof a multi-phase electrical power distribution system.
 8. The device ofclaim 1, wherein identifying the electrical phase associated with thesource of the electromagnetic emission comprises determining that aphase of the output signal from the sensor is within an expected laggingrange from the reference signal.
 9. The device of claim 1, whereinoutputting the indication of the electrical phase comprises providing anindication of the electrical phase to a display of the device.
 10. Thedevice of claim 1, wherein outputting the indication of the electricalphase comprises transmitting the indication of the electrical phase to aserver system.
 11. The device of claim 1, wherein: the sensor comprisesa first sensor configured to detect a first type of electromagneticemission and generate a first output signal representative of theelectromagnetic emission detected by the first sensor, and the devicefurther comprises a second sensor configured to detect a second type ofelectromagnetic emission and generate a second output signalrepresentative of the electromagnetic emission detected by the secondsensor.
 12. The device of claim 11, the operations comprising: obtainingthe second output signal from the second sensor; and identifying thesecond output signal as a dominant signal over the first output signal,wherein comparing the output signal to the reference signal comprisescomparing the second output signal with the reference signal based onidentifying the second output signal as a dominant signal over the firstoutput signal.
 13. The device of claim 11, the operations comprising:obtaining the second output signal from the second sensor; determiningthat a phase of the first output signal falls outside of an expectedlagging range from the reference signal; determining that a phase of thesecond output signal falls within the expected lagging range from thereference signal; and based on determining that the phase of the firstoutput signal falls outside of the expected lagging range from thereference signal, and that the phase of the second output signal fallswithin the expected lagging range from the reference signal, identifyingthe first output signal as an outlier signal, wherein comparing theoutput signal to the reference signal comprises: comparing the secondoutput signal to the reference signal; and excluding the first outputsignal from comparison with the reference signal based on identifyingthe first output signal as an outlier signal.
 14. The device of claim11, the operations comprising: combining the first output signal and thesecond output signal into a combined output signal, wherein comparingthe output signal to the reference signal comprises comparing thecombined output signal to the reference signal.
 15. The device of claim11, wherein the first sensor is an electric field sensor, and whereinthe second sensor is one of a magnetic field sensor, an infrared sensor,a visible light sensor, or an ultraviolet light sensor.
 16. Theelectrical phase identification device of claim 1, further comprising asecond sensor configured to detect a second type of electromagneticemission, wherein the second sensor is an infrared sensor, a visiblelight sensor, or an ultraviolet light sensor; wherein the sensor is afirst sensor configured to configured to detect a first type ofelectromagnetic emission, wherein the first sensor is an electric fieldsensor or a magnetic field sensor, wherein the reference signal issynchronized with an alternating current (AC) phase of a multi-phaseelectrical power distribution system, wherein the output signal is afirst output signal representative of the first type of electromagneticemission detected by the first sensor, wherein the operations furthercomprise obtaining an second output signal from the second sensor, thesecond output signal representative of the second type ofelectromagnetic emission detected by the second sensor, and whereinidentifying the electrical phase comprises identifying, based oncomparing respective phases of the first and second output signals tothe reference signal, a particular AC phase of the multi-phaseelectrical power distribution system associated with a source of thefirst and second types of electromagnetic emissions.
 17. A phasedetection method executed by one or more processors, the methodcomprising: obtaining a reference signal; obtaining an output signalfrom a sensor, the output signal representative of an electromagneticemission detected by the sensor; identifying, based on comparing theoutput signal to the reference signal, an electrical phase associatedwith a source of the electromagnetic emission; and outputting anindication of the electrical phase.
 18. The method of claim 17, whereincomparing the output signal to the reference signal comprisesdetermining a first phase offset between the output signal and thereference signal.
 19. The method of claim 18, wherein identifying theelectrical phase associated with the source of the electromagneticemission comprises: determining a second phase offset between thereference signal and an alternating current (AC) phase of a multi-phaseelectrical power distribution system; and determining the electricalphase associated with the source of the electromagnetic emission basedon (i) the first phase offset between the output signal and thereference signal and (ii) the second phase offset between the referencesignal and the AC phase of the multi-phase electrical power distributionsystem.
 20. The method of claim 17, wherein the reference signalcomprises a global positioning system clock signal.
 21. The method ofclaim 17, wherein the sensor is a first sensor comprising an electricfield sensor or a magnetic field sensor configured to detect a firsttype of electromagnetic emission, wherein obtaining the output signalfrom the sensor comprises obtaining a first output signal from the firstsensor, the method further comprising: obtaining a second output signalfrom a second sensor, wherein: the second sensor comprises an infraredsensor, a visible light sensor, or an ultraviolet light sensor and isconfigured to detect a second type of electromagnetic emission, and thesecond output signal is representative of the electromagnetic emissiondetected by the second sensor; and identifying, based on comparing thefirst output signal and the second output signal to the referencesignal, the electrical phase associated with the source of theelectromagnetic emissions.
 22. A non-transitory computer readablestorage medium storing instructions that, when executed by at least oneprocessor, cause the at least one processor to perform operationscomprising: obtaining a reference signal; obtaining an output signalfrom a sensor, the output signal representative of an electromagneticemission detected by the sensor; identifying, based on comparing theoutput signal to the reference signal, an electrical phase associatedwith a source of the electromagnetic emission; and outputting anindication of the electrical phase.
 23. The non-transitory computerreadable medium of claim 22, wherein the sensor is a first sensorcomprising an electric field sensor or a magnetic field sensorconfigured to detect a first type of electromagnetic emission, whereinobtaining the output signal from the sensor comprises obtaining a firstoutput signal from the first sensor, the operations comprising:obtaining a second output signal from a second sensor, wherein: thesecond sensor comprises an infrared sensor, a visible light sensor, oran ultraviolet light sensor and is configured to detect a second type ofelectromagnetic emission, and the second output signal is representativeof the electromagnetic emission detected by the second sensor; andidentifying, based on comparing the first output signal and the secondoutput signal to the reference signal, the electrical phase associatedwith the source of the electromagnetic emissions.